(CNN)Former Secretary of State Condoleezza Rice says she has confidence in special counsel Robert Mueller and believes "nobody should try to impede" his investigation into Russian interference in the 2016 election.
Rice on Mueller probe: 'Nobody should try to impede the investigation'
"He is a terrific person, straight shooter," Rice said of Mueller in a wide-ranging conversation with David Axelrod on "The Axe Files," which aired at 7 ET Saturday night. "I think he'll -- he will push to a conclusion. I don't have any idea what it will be. I hope, frankly, it's over pretty soon, because we need to get on with our business."
When asked about Trump's characterization of the Russia probe as a hoax, Rice said: "Well, the President shouldn't call it a hoax. Let's just say that. But the fact is we will get to the bottom of what happened. I hope that there are people spending as much time trying to figure out exactly how the Russians did what they did."
Asked if it would be a mistake for Trump to fire Mueller or to try to impede the investigation, Rice said: "I'm not going to try to give advice, and nobody should try to impede the investigation."
Rice, who was former President George W. Bush's secretary of state and national security adviser, also discussed Trump's tweets on the nuclear threat from North Korea, including one comparing size of his his "nuclear button" to North Korean leader Kim Jong Un's, saying she doesn't think such tweets are helpful.
"I've been no fan of the tweets, the policy by tweets," Rice said. "I've been no fan of that, but I also think it didn't deserve -- square column inches of analysis."
"Nuclear war though is a pretty serious deal," Axelrod continued.
"Yes, nuclear war is a very serious deal, but I think people would be mistaken to think that because the President has an ill-advised tweet, we're about to have nuclear war with the North Koreans," Rice replied.
Asked whether she was concerned about misinterpretations or provocation over the tweets, Rice said she thought the North Korean leader was turning out to be more clever than she thought.
"The approach to the South Koreans was clever; the decision to go to the Olympics is clever," Rice said referring to North Korea's overtures on meeting with South Korea to ease military tensions between the two countries. "I think he is more isolated than his father was. Perhaps certainly more reckless. I wonder sometimes if he really believes it when he says, 'I can destroy the United States,' because anybody who tells (him) something he doesn't want to hear seems to get killed."
And that "is a real disincentive to tell him the truth," Rice added.